The crisis in South Sudan posed the longest-range test for the Marine quick reaction force created after the much-criticized response to last year's terrorist attack on the U.S. consulate in Libya that killed Ambassador Christopher Stevens and three other Americans.
On Monday, 150 Marines from the Special Purpose Marine Air-Ground Task Force for crisis response, based in Moron, Spain, flew aboard their MV-22 Osprey tilt-rotor aircraft more than 3,400 miles to the U.S. military hub for East Africa at Camp Lemonnier, Djibouti.
The next day, 50 of those Marines flew to Entebbe, Uganda, to be closer to South Sudan as a precautionary move should they be needed to evacuate Americans and foreign nationals, or provide security for the U.S. Embassy in Juba, the capital of South Sudan.
The arriving Marines bolstered the East Africa Response Force, a Djibouti-based joint U.S. military force that is part of the Africa Command (AFRICOM) led by Army Gen. David Rodriguez.
In a statement earlier this week, AFRICOM said, "One of the lessons learned from the tragic events in Benghazi was that we needed to be better postured in order to respond to developing crisis situations, if needed. These precautionary movements will allow us to do just that."
Following Benghazi, about 550 Marines and six Ospreys were sent to the U.S. air base at Moron to serve as a quick reaction force for threats to U.S. citizens and diplomatic personnel across North Africa.
The main Marine emergency response force for crises worldwide remains the Marine Expeditionary Unit based on ships but "the Mediterranean currently doesn't have a dedicated MEU for the Med," said Capt. Eric Flanagan, a Marine spokesman.
Last weekend, three U.S. Air Force CV-22 Ospreys took ground fire when they attempted to evacuate Americans from the South Sudanese town of Bor. Four U.S. troops aboard the aircraft – all Navy SEALS, according to the Associated Press – were wounded in the "lower extremities" and have been listed in stable condition, Pentagon officials said.
About 380 American citizens have thus far been evacuated from South Sudan to Nairobi, Kenya, by four charter flights and five flights by Lockheed Martin Corp.-made C-130 aircraft, along with 300 nationals from other countries, the State Department said in a statement.
Other U.S. nationals may have left South Sudan on their own, the State Department said, but about 3,000 citizens from countries such as Canada, Britain, Australia and Kenya are still believed to be in South Sudan, according to the United Nations.
On Thursday, African leaders from neighboring states tried to serve as mediators in advancing peace talks between South Sudan President Salva Kiir, an ethnic Dinka, and former Vice Persident Riek Machar, from the Nuer community.
Kenyan President Uhuru Kenyatta and Ethiopian Prime Minister Hailemariam Desalegn had "a constructive dialogue" with Kiir in Juba but Machar, whose whereabouts were not immediately known, did not attend, said South Sudan's Foreign Minister Barnaba Marial Benjamin.
Kiir has accused Machar of attempting to mount a coup to topple the government of the world's newest independent state. The African leaders were pressing for talks in Nairobi between Kiir and Machar, the Associated Press reported.
The factional fighting in South Sudan has provoked fears of a civil war in the country that peacefully broke away from Sudan in 2011, following a 2005 peace deal.